Internal combustion engines generate heat during the combustion process. About half of the energy generated by the combustion process may be delivered to the flywheel of the engine. The discharged heat energy that is not used to perform useful work is typically known as “waste heat.” Waste heat recovery (“WHR”) systems aim to capture some of the waste heat energy by recovering heat energy and using it to drive an expander to convert the recovered heat energy to power, thereby potentially increasing the combustion efficiency. Example expanders include turbines and pistons.
Some WHR systems utilize a Rankine cycle (“RC”). The RC is a thermodynamic process in which heat is transferred to a working fluid in an RC circuit. The working fluid is pumped to a boiler where it is vaporized. The vapor is passed through an expander and then through a condenser, where the vapor is condensed back to a liquid. The expanding working fluid vapor causes the expander to rotate, thereby converting the waste heat energy to mechanical energy. The mechanical energy may be transmitted to engine system components, such as a pump, a compressor, a generator, etc.
WHR systems are complex, require fluid circuits, and include many components that add weight to any vehicle powered by the internal combustion engine. Accordingly, it is desirable to provide an improved WHR system that is more compact and less complex than present WHR systems.
The background of the disclosure is described herein to explain the context of the present invention. This is not to be taken as an admission or a suggestion that any of the material referred to was published, known or part of the common general knowledge in the art to which the present invention pertains, in the United States or in any other country, as at the priority date of any of the claims.